Oscillation device of magnetic escapement



Nov. 22, 1966 SHUJI ANDO 3,286,457 OSCILLATION DEVICE OF MAGNETIC ESCAPEMENT Original Filed March 20, 1962 J5 United States Patent f 3,286,457 OSCILLATION DEVICE 0F MAGNETIC ESCAPEMENT Shuji Ando, Tokyo-to, Japan, assignor to Kabushiki Kaisha Hattori Tokeiteu Ginza, Chuo-ku, Tokyo-to, Japan, a joint-stock company of Japan Original application Mar. 20, 1962, Ser. No. 181,051.

Divided and this application July 25, 1963, Ser.

Claims priority, application Japan, Apr. 19, 1961,

36/13,715, 36/131,716 6 Claims. (Cl. 58116) This application is a division of abandoned application Serial No. 181,051, filed March 20, .1962.

This invention relates to timekeepers of the type regulated by magnetic escapements, and more particularly it relates to improvements in the oscillation device of magnetic escapements.

It is an object of the present invention to provide means for stabilizing the timekeepingaccuracy of timekeepers with magnetic escapements over a much longer period than hither-to possible.

It is another object of the invention to provide means whereby the oscillating member of a magnetic escapement can be easily caused to have the same oscillation frequency over a much wider range of driving power than hitherto possible.

It is yet another object of the invention to increase the Q of the oscillating member so that, when the oscillating member undergoes forced oscillation, the lag from the natural oscillation frequency due to the eifect of the driving power is made as small as possible.

It is a further object of the invention to provide means for preventing the mutual positional relationship between the magnet, which is the oscillating member, and the escape wheel, which is magnetically coupled thereto, from being disturbed by some unforeseen cause.

The nature and details of the invention as well as the manner in which the foregoing objects may best be achieved will be more clearly apparent from a consideration of the following description when taken in conjunction with the accompanying drawings in which like parts are designated by like reference numerals and characters, and in which:

FIG. 1 is an enlarged plan view, in section and with parts out ofr", showing the important parts of an embodiment of the invention;

FIG. 2 is a perspective view showing the embodiment of FIG. 1 with some parts in an exploded state;

FIG. 3 is a perspective view, with some parts cut off, showing a conventional magnetic escapement; and

FIG. 4 is a fragmentary view in perspective illustrating another form of adjusting means for varying the position of the tube that supports the magnet.

In general, in a timekeeper regulated by a magnetic escapement, fluctuations in the power source and fluctuations of the power transmitted through the wheel train cause the torque transmitted to the escape wheel to vary.

A preferred embodiment of the invention will now be described with reference to FIGS. 1, 2 and 3. In a conventional magnetic escapement as shown in FIG. 3, the end of a read spring 12, the other end of which is fixed rigidlv to a magnet 11, is fixed to a block 13, and a shaft member 14 which supportsthis block 13 is supported in the state of a cantilever beam supported at its fixed end by a base plate 15. For the purpose of adjusting the degree of magnetic coupling of the magnet relative to the escape wheel 16, a hole 17 is provided in the block 13 for engagement with a handle for rotating this block 13 together with the shaft member 14.

In a magnetic escapement of this type, in order to obtain escapement operation of high accuracy, it is neces- 3,286,457 Patented Nov. 22, 1 966 ICC sary that the magnetic coupling between the two poles of the magnet and the escape wheel which is interposed therebetween be such that a gap of 0.1 to 0.15 mm. is positively maintained between each said pole and the escape wheel.

In the escapement shown in FIG. 3, however, the shaft member 14 supporting the magnet 11 is a cantilever beam supported at its fixed end by the base plate 15. Moreover, it is necessary that this shaft member 14 be so supported by the base plate 15 that it is rotatable relative to the base plate. 15 in accordance with adjusting movements imparted by way of the hole 17 during adjustment of the degree of magnetic coupling of the magnet 11 with respect to the escape wheel 16. Because of such features as described above, it is diflicult to obtain continuous oscillation with the. magnet 11 maintained in a positively fixed position. Consequently, the gaps provided on both sides of the escape wheel are subject to variation, or a pole of the magnet may be displaced by attractive force, whereby the timekeeping accuracy of the timekeeper drops. Such defects eventually cause impairment of the performance of the timekeeper.

Furthermore, the conventional supporting members have masses which are not large compared with those of the oscillating members. Consequently, they are subjected to the reaction of the oscillating members and tend to damp the oscillating members and tend to damp the oscillation. However, by increasing the mass of the supporting member, itis possible to prevent the absorption of the oscillation.

The present invention, in this aspect thereof, increases the accuracy of the escapement operation of the escape wheel by supporting the oscillatory magnet in a positively fixed position. The invention furthermore enables adjustment of the degree of magnetic coupling between the magnet and the escape wheel to be made without varying the fixed support position of the magnet; moreover, it enables fine adjustment. The invention also prevents damping of the oscillation of the magnet. The details of the manner in which these and other advantages are achieved are described below.

Referring to FIGS. 1 and 2, which illustrate one embodiment of the present invention, a reed spring 22, fixed at one end to a magnet 11, is secured at its other end by means of screws 27 to a seat block 23a which is integrally provided on a long sleeve or tube 23 having ample mass. The tube 23 is snugly but rotatably fitted over an arbor 24, the ends of which are fixed to base plates 15 of the timekeeper. A spring 18 is fitted between one end of the tube 23 and one of the base plates 15 so as to press the tube 23 elastically against the other base plate 15. A lever 19 is fixed perpendicularly to the end of the tube 23 opposite from the spring 18 and has, at its swinging end, a manipulating piece 20, which moves in a slot 21formed in the base plate 15. The end of the piece 20 is threaded to engage with a nut 25, by means of which the adjusted position of the piece 20 in the slot 21 can be secured.

Since, as described above, the member which supports the reed spring 22, that is, the magnet 11, is a long tube 23, and since this tube is supported rotatably on an arbor 24 which is fixed at both ends, the reed spring, that is, the magnet, is positively held against any unintentional shifting of position. Accordingly, the magnet is caused to oscillate with its correct coupling position constantly maintained with respect to the escape wheel (not shown) with which the magnet is magnetically coupled, whereby the accuracy of magnetic escapement operation is greatly increased.

The degree of magnetic coupling of the magnet and escape wheel is adjusted by rotating the lever 19. In this case also, since the long tube 23 is caused to rotate over 3 the arbor 24 which is fixed at both ends, only the inclination of the magnet about the axis of the tube 23 Y with respect to the escape wheel varies, and no displacement whatsoever takes place to disturb the gaps between the magnetic poles and the escape wheel. Accordingly, the cause for impairment of timekeeping performance is eliminated, and stable escapement operation is obtainable. Moreover, since this adjustment is accomplished through rotation of the tube 23 by means of the lever 19 which is integrally secured thereto, fine adjustment becomes possible. Furthermore, since the tube 23 which supports the magnet 11 has an amply large mass, it does not absorb the oscillation of the magnet. Accordingly, the damping of the magnet oscillation is reduced, and the efficiency of the device is increased.

As shown in FIG. 4, the invention further contemplates provision of a worm gearing arrangement for effecting minute adjustment of the position of the magnet. This figure only illustrates portions of the structure, it being understood that the support plates 15 and magnet as shown in FIGS. 1 and 2 are similarly related to the structure of FIG. 4. In this figure, the tube is provided with gear teeth 27, which are in mesh with worm wheel 26, which receives rotation from a shaft 26a. Since the tube is rotatably mounted on the arbor 24, turning of the shaft 26a turns the tube and thus, the magnet carried by the seat block 23a.

It is, thus, seen that the gear teeth 27 in FIG. 4 and the lever 19 in FIG. 1 are in effect turning moment imparting means associated with the tube and that actuating means are associated with same by, respectively, the worm gear and its shaft in FIG. 4 and the bolt or screw 20 in FIG. 1, which is a manipulating member so that moving these latter components positions the tube and magnet relative to the escape wheel.

Further, if it is desired to lock the magnet support mechanism and adjust the position after the tube 23 has been turned by either manipulation of the lever 19 via movement of screw 20 in slot 21 or by Way of turning movement being imparted to the tube by actuation of the worm gearing, a substance such as lacquer or adhesive could be applied to the underside of the head of the nut 25 in FIG. 1 or on the teeth of the worm gearing. This locking of the mechanism adjusting position will prevent changes due to vibration of the portion of the magnet relative to the escape wheel.

Although this invention has been described with respect to particular embodiments thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention, as defined by the appended claims.

What is claimed is:

1. In a magnetic escapement for a timepiece of the type having a magnet as an oscillating member and an escape wheel with which said magnet is magnetically coupled, a magnet supporting mechanism comprising a combination of spaced structural timepiece components, an arbor fixed at opposite ends between such components, a tube rotatably mounted on said arbor, a seat block carried by the tube for receiving and supporting a magnet, turning moment imparting means carried by said tube and capable upon actuation of turning said tube and thereby said magnet to impart fine adjustment of the position of the seat block and the magnet carried thereby relative to the escape wheel and means for actuating said turning moment imparting means to effect such fine adjustment.

2. In a magnetic escapement for a timepiece as claimed in claim 1 and said turning moment imparting means comprising a lever extending perpendicularly from and fixed to said tube, one of said structural components having a slot therein, and the means for actuating said turning moment imparting means comprising a manipulating member carried by the lever and disposed in said slot whereby the position of the lever and thus, the tube can be altered for effecting fine adjustment of said magnet and means for securing said manipulating member in position relative to said slot after fine adjustment has been eifected.

3. In a magnetic escapement for a timepiece as claimed in claim 1 and said turning moment imparting means comprising gear teeth operably associated with said tube, and means for actuating said turn moment imparting means comprising a worm in mesh with said teeth and means for turning said worm to thereby turn said tube to efiect fine adjustment of the magnet relative to said escape wheel.

4. In a magnetic escapement for a timepiece as claimed in claim 2 and an adhesive coating operably associated with said means for securing the lever in adjusted position relative to said slot so as to lock the lever in adjusted position so as to prevent change due to vibration of the portion of the magnet relative to the escape wheel.

5. In a magnetic escapement for a timepiece as claimed in claim 3 and an adhesive coating applied to at least one of said worm and gear teeth to lock the same and thus, the tube and magnet in adjusted position so as to prevent change due to vibration of the portion of the magnet relative to the escape wheel.

6. In a magnetic escapement for a timepiece as claimed in claim 1 and said tube having less extent axially of the arbor than the space between said spaced structural components and resilient means biased between one end of the tube and an adjacent structural component for elastically pressing the tube against the other structural component.

RICHARD B. WILKINSON, Primary Examiner.

' LEO SMILOW, Examiner.

G. F. BAKER, Assistant Examiner. 

1. IN A MAGNETIC ESCAPEMENT FOR A TIMEPICE OF THE TYPE HAVING A MAGNET AS AN OSCILLATING MEMBER AND AN ESCAPE WHEEL WITH WHICH SAID MAGNET IS MAGNETICALLY COUPLED, A MAGNET SUPPORTING MECHANISM COMPRISING A COMBINATION OF SPACED STRUCTURAL TIMEPIECE COMPONENTS, AN ARBOR FIXED AT OPPOSITE ENDS BETWEEN SUCH COMPONENTS, A TUBE ROTATABLY MOUNTED ON SAID ARBOR, A SEAT BLOCK CARRIED BY THE TUBE FOR RECEIVING AND SUPPORTING A MAGNET, TURNING MOMENT IMPARTING MEANS CARRIED BY SAID TUBE AND CAPABLE UPON ACTUATION OF TURNING SAID TUBE AND THEREBY SAID MAGNET TO IMPART FINE ADJUSTMENT OF THE POSITION OF THE SEAT BLOCK AND THE MAGNET CARRIED THEREBY RELATIVE TO THE ESCAPE WHEEL AND MEANS FOR ACTUATING SAID TURNING MOMENT IMPARTING MEANS TO EFFECT SUCH FINE ADJUSTMENT. 